1058
Russ.Chem.Bull., Int.Ed., Vol. 54, No. 4, April, 2005
A. B. Sheremetev
Scheme 1
in water (40 mL) was simultaneously added dropwise from a
second dropping funnel at a temperature no higher than 30 °C.
Then a mixture was heated to 95 °C over 1.5 to 2 h and urea (6 g,
0.1 mol) was added in one portion. The resulting mixture was
refluxed for 3 h and cooled. The precipitate that formed was
filtered off, washed with water, dried, and recrystallized from
CHCl3—light petroleum (1 : 1). Found (%): C, 53.66; H, 3.43;
N, 23.41. C8H6FN3O. M = 179.15. Calculated (%): C, 53.63;
H, 3.38; N, 23.45. IR (KBr), ν/cm–1: 3448, 3324, 3248, 1632,
1612, 1576, 1536, 1488, 1396, 1312, 1248, 1164, 1104, 1056,
As can be seen in Table 1, hetarylꢀAF derivatives were
obtained by this method in satisfactory to high yields.
Note also that the yields of all earlier known compounds
increased.
Thus, we developed a simple general oneꢀpot method
for the synthesis of 3ꢀaminoꢀ4ꢀarylꢀ and 3ꢀaminoꢀ
4ꢀhetarylfurazans from alkyl βꢀarylꢀ and βꢀhetarylꢀ
βꢀoxopropionates, which involves cascade heterocycliꢀ
zation.
1
984, 884, 848. H NMR (DMSOꢀd6), δ: 6.22 (br.s, 2 H, NH2);
7.37 (t, 2 H, CH=CF, J = 8.7 Hz); 7.82 (dd, 2 H, CH—C—Het,
J = 5.5 Hz). 13C NMR (DMSOꢀd6), δ: 116.2 (d, CH=CF, J =
21.6 Hz); 122.1 (d, Ci, J = 2.6 Hz); 130.2 (d, CH—C—Het, J =
8.6 Hz); 146.2 (C—Ar); 155.3 (C—NH2); 163.3 (d, C—F, J =
246.7 Hz). 19F NMR (DMSOꢀd6), δ: –109.5.
Other AF given in Table 1 were obtained analogously. Their
spectral characteristics were identical with those of authentic
samples. The mass spectra of all the products contain an intense
molecular ion peak and a signal for the fragment [M – NO]+
characteristic of furazan derivatives.
Experimental
Melting points were determined with a Gallenkamp unit
(Sanyo Co.). Naturalꢀisotope 1H and 13C NMR spectra were
recorded on a Bruker AMꢀ300 spectrometer (300.13 and
75.7 MHz, respectively). Chemical shifts are given in the δ scale
with a solvent as the internal standard. Mass spectra were reꢀ
corded on Finnigan MAT INCOSꢀ50 and Varian MAT CHꢀ111
instruments (EI, 70 eV). IR spectra were recorded on a
Perkin—Elmer Model 577 spectrometer (in pellets with KBr).
The course of the reaction was monitored and the purity of the
products was checked by TLC on Silufol UVꢀ254 plates; spots
were visualized with UV irradiation.
References
Synthesis of 3ꢀaminoꢀ4ꢀ(4ꢀfluorophenyl)furazan (general proꢀ
cedure). Methyl 4ꢀfluorobenzoylacetate (19.6 g, 0.1 mol) was
added at 0 °C to a solution of NaOH (4.4 g, 0.11 mol) in water
(50 mL) and the resulting mixture was stirred for 12 h. Sodium
nitrite (8.3 g, 0.12 mol) was added and then 20% HClO4
(0.23 mol) was slowly added dropwise at T <10 °C. After the
acid was added completely, the reaction mixture was warmed to
room temperature and left for ~14 h. Then a solution of
NH2OH•HCl (27.8 g, 0.4 mol) in water (50 mL) was added
dropwise with vigorous stirring. After half the solution of
hydroxylamine was added, a solution of NaOH (18 g, 0.45 mol)
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Izv. Akad. Nauk, Ser. Khim., 2005, 1007 [Russ. Chem. Bull.,
Int. Ed., 2005, 54, 1032].
2. V. G. Andrianov and A. V. Eremeev, Khim. Geterotsikl.
Soedin., 1984, 1155 [Chem. Heterocycl. Compd., 1984 (Engl.
Transl.)].
3. A. B. Sheremetev, N. N. Makhova, and W. Friedrichsen,
Adv. Heterocycl. Chem., 2001, 78, 65.
4. S. A. Steklova, O. A. Zagulyaeva, V. V. Lapachev, and
V. P. Mamaev, Khim. Geterotsikl. Soedin., 1980, 822
[Chem. Heterocycl. Compd., 1980, 16, 640 (Engl. Transl.)];
Sheremetev
